Filter system for dry cleaning solvents



Aug. 10, 1965 M. SALYER, JR

FILTER SYSTEM FOR DRY CLEANING SOLVENTS 2 Sheets-Sheet 1 Filed Aug. 15, 1962 COOLANT COOLANT OUT INVENTOR B. M. SALYER JR.

FIG.I

ATT 0 R Nil Aug. 10, 1965 M. SALYER, JR

FILTER SYSTEM FOR DRY CLEANING SOLVENTS 2 Sheets-Sheet 2 Filed Aug. 15, 1962 INVENTOR. B. M. SALYER JR.

ATTORNEYS United States Patent 3,199,679 FILTER SYSTEM FOR DRY CLEANWG SOLVENTS Bert Montgomery Saiyer, J13, 3111 NW. 19th, Uislahoma Qty, Okla. Filed Aug. 15, 1962, Ser. No. 217,196 3 (Iiaims. (Cl. 2199-259) The instant application is a continuation-in-part of application Serial No. 152,792, filed November 16, 1961.

This invention relates to the sol-vent cleaning of fabrics. Specifically, this invention relates to a filtration system to be used in a solvent-type dry cleaning plant. In particular this invention relates to a filtration system for removing impurities from a dry cleaning solvent, such impurities including solid particles, fatty acids, greases and odorous substances.

Generally dirt, spots, stains and the like can be and are removed from fabrics such as wool, silk, rayon and/ or synthetic fabrics by what is termed a dry cleaning process. Such a process utilizes a liquid solvent to be circulated across and through the soiled fabric in the cleaning thereof. Most modern day cleaning establishments use synthetic solvents such as carbon tetrachloride, trichlorotrifluoroethane, trichloroethylene, perchloroethylene and various blends of chlorinated hydrocarbons. Since most of the spots and stains on clothing and the like are of an oily nature, these synthetic organic solvents effectively remove them by dissolving the oils, greases, waxes and tars of such spots and stains.

Also present in most soiled fabrics of the above described type are insoluble particles such as lint, earth, dust, ashes, carbon particles and solids such as talcum and the like. These, too, are mechanically removed with the same solvent.

In the usual dry cleaning plant the cleaning solvent is caused to circulate through the soiled fabrics. In so doing the solvent both dissolves and removes the oily spots and loosens the solid particles contained in the fabrics so that they become suspended in the solvent. Clearly, when the solvent is removed from the fabrics at the end of the cleaning process it will be found to be contaminated with the impurities, both soluble and insoluble, that it removed from the soiled fabrics.

One of the most undesirable impurities found in a used cleaning solvent is fatty acids. These fatty acids are introduced into the solvent by the soiled fabrics and the detergents used in the dry cleaning process. However, the greatest sources of fatty acids contained in the dry cleaning solvent are dry cleaning soaps and prespotters. Obviously, as the use of a solvent continues these fatty acids, along with other undesirable impurities, tend to accumulate to a concentration that is detrimental to the efficiency of the dry cleaning process. When these fatty acids reach an excessive concentration in the solvent they tend to oxidize to produce an offensively odorous substance that invades the fabrics to be cleaned. Excessive amounts of fatty acids also tend to discolor the fabrics and adversely affect the efficiency of the dry cleaning soaps and detergents. It is therefore necessary to either remove these fatty acids and other solvent impurities or continuously add fresh solvent to the process. Because of the expense of these solvents the former alternative is the preferred one.

Dry cleaning plants of today utilize various methods for purifying contaminated solvents. Some of these methods are, (l) mechanically filtering insoluble contami nants such as dirt particles and the like from the solvents, (2) adsorbing the soluble contaminants such as fatty acids onto adsorbent particles such as activated clays or carbon, (3) removing both soluble and insoluble contaminants by distillation of the contaminated solvent, and

3,199,679 Patented Aug. to, 1965 (4) combining the distillation, filtration and adsorption methods The mechanical filters used to remove the insoluble contaminants are not always effective because of the tendency of the oils and greases removed from the fabrics to collect on the filters, forming a thick gummy matter and clogging the filter. This requires frequent and time consuming shut down to clean the relatively large filters.

The purification of dry cleaning solvents through the use of particles of adsorptive materials alone generally gives incomplete results since some of the soluble contaminants and all of the insoluble contaminants are un-. affected by these materials.

Purifying the solvent by distillation requires the incorporation of a still in the dry cleaning process and also the periodic shutting down of the cleaning process for thedistil-lation of the solvent. This is undesirable from an economic point of view. It has also been found that this method is not always efiective; that some of the fatty acids and odors distill over into the condensed, purified solvent.

It is therefore an object of this invention to provide a filtration system for use in synthetic solvent dry cleaning systems which overcomes the objections to prior filtering devices and which provides economic, eificient and continuous operation of the cleaning system.

Another object of this invention is to provide a filtration system for a solvent-type dry cleaning plant that is relatively simple, inexpensive and effective in removal of both soluble and insoluble impurities from the cleaning solvent.

It is a further object of this invention to provide a filtration system consisting of two or more removable and replaceable filter cartridges that can be placed in the solvent circulation system of a solvent-type dry cleaning plant for the continuous removal of both soluble and insoluble impurities from the solvent.

Further objects and advantages of this invent-ion will be apparent from the following description and appended claims, reference being had to the accompany drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

:FTGURE l is a schematic representation of a solventtype dry cleaning plant incorporating the filtration system of this invention.-

FIGURE 2 is an elevational, part sectional, view of the two filter cart-ridges that comprise the filtration system of this invention.

FIGURE 3 is a cross-sectional view of filter A in FIGURE 2, taken along line 33.

FIGURE 4 is a cross-sectional View of filter B in FIGURE 2, taken along line 44.

Description Reference is now made to the various figures for purposes of describing this invention. As schematically shown filter cartridges A and B are interconnected by a tubular conduit 7 0 such that the direction of solvent flow through both filters is from the outside-in. Substantially cylindrical outer cannister 10 of filter A is provided with a plurality of radial perforations 18. Lip portions 20 are preferably formed on the outside surface of cannister 10 by a punch process which simultaneously produces the perforations 18. Preferably, the lip portions 2t) are formed so as to be in the same direction to give the desired flow characteristics hereafter described. Disposed coaxially with the cannister ll) is an inner cannister 12. This innor cannister 12, like the outer cannister, is provided with a plurality of perforations 22 and lip portions 24. The solvent is caused to flow semi-circulatory through the filter A in a turbulent manner by first off-setting inner perforations 22 with respect to outer perforations 18 and by positioning the lip portions 29 and 24 in the same flow direction.

Inner and outer cannisters 12 and 10, respectively, are connected together and closed at their respective ends by top and bottom plates 14 and 16, respectively. These plates are attached to the end of the cannisters in any conventional manner, as for example soldering. Bottom closure plate 16 is provided with axial perforation 17 for connection with outlet conduit 70. The annular space 13 between cannisters 10 and 12 is filled with an alkali impregnated cellulose material 28 such as ground up paper board, or similar paper product, the purpose of which will be described hereinafter. Disseminated throughout the annular bed of cellulose material 28 are a multiplicity of long irregular strands or fibers 2 of a rosin-less material such as aspen wood, sisal, hemp or excelsior. The length of these fibers is from three to five inches although other lengths may be used as de sired. These fibers tend to swell when wetted by the cleaning solution and, as discovered, will create and maintain a plurality of tortuous flow paths through the cellulose material. This prevents excessive compacting of solvent Wetted cellulose material which would shut off the flow of solvent therethrough. V

A sock or sleeve 26 of synthetic cloth material such as nylon or Orlon fits snugly around the outer surface of the inner cannister 12. The purpose of this sleeve is to remove any superfines from the solvent circulating therethrough and to prevent the finely divided cellulose material 28 from becoming entrained in the solvent. Because of the character of this cloth material it is unafi'ected by the solvent.

It has been found that cellulose material 28 is highly effective in removing and controlling the fatty acids that tend to accumulate in dry cleaning solvents. Although it cannot be fully understood, it appears the cellulose material 28 has a neutralizing effect towards these acids to prevent their build-up. In the production of paper from wood or wood pulp the wood chips or pulp are commonly contacted with caustic soda (NaOI-I). At one point in the paper making process, depending upon the procedure followed, this caustic soda is removed from the wood pulp. However, this removal process is not 100% effective therefore a fraction (approximately or less) of the caustic soda remains in the Wood pulp. Likewise, this caustic soda is present in the paper product produced from such wood pulp. When a fatty acid contacts such a paper product it will react with the caustic soda contained therein to produce a relatively insoluble soap. This soap will tend to settle out of the solvent and collect on the filter surfaces of this filtration system.

It should be noted that not only does this cellulose material serve as a chemical filter of the cleaning solvent but serves also as an additional mechanical filter, for solid insolubles.

Referring now to filter cartridge B as illustrated in FIGURES 2 and 4. The cartridge is constructed similar to filter A for the same or similar flow conditions, but performs added functions in the overall filtering system of this invention. Perforated, substantially cylindrical, cannister 30 has disposed coaxially therein a similar but smaller diameter, perforated, substantially cylindrical cannister 36. Cannisters 3t and 36 are provided. with perforations 32 and 38 and inclined lip portions 34 and 40 respectively. The use and purpose of these perforations and lip portions are the same as the use and purpose of the corresponding parts in cannisters l0 and 12 of filter A as above described.

Top and bottom plates 42 and 44, respectively, close and interconnect the ends of the cannisters 30 and 36. Centrally located perforation 45 provided in bottom plate 44 is connected to an outlet conduit, not shown.

Exteriorly surrounding the cannisters 3t) and 36 are bristle blankets 43 and 50, respectively, retained thereabout by any conventional means such as binding means (not shown). These bristle blankets are produced from a natural fiber material such as hemp, jute, abaca or sisal. synthetically produced fibers such as fiberglass may also be used. Variable lengths of the irregular, relatively flexible, fibrous blanket material are deposited in a random pattern to form the continuous bonded-like yet porous blanket.

Conventional mechanical filters for solvent-type dry cleaning plants tend to become clogged by the congealed greases, oil, soaps and the like that are removed from the fabrics and suspended in the relatively cool cleaning solvent. This results in a blinding off of solvent flow necessitating frequent and undesired shut down for cleaning or replacing the filter.

Due to the loose, rough character of the blankets 48 and 50 they possess excellent mechanical filtering characteristics for the removal of these congealed greases and the like, without blinding off. Each blanket essentially traps the solid impurities of the solvent yet remains open sufficiently to provide for many cleaning flow cycles.

Disposed Within the annular space between the blanket 53 and the cannister 39 is a packed bed 5?. of activated carbon or other similar adsorbent material. Odors and dye color bodies contained within the solvent will be at least partially removed therefrom by adsorption onto the carbon particles as the solvent flows through the carbon bed 52..

In operation, the filters A and B are enclosed in filter cartridge receptacles 68 and 72, respectively, and are series connected directly into the solvent circulation cycle as shown schematically in FIGURE 1. Solvent is drawn from storage tank till through conduit 62 into pump 64 from which it is discharged through conduit 66 into vessel 68 containing filter A. Solvent flows through the filter A, outside-in, as above described, thence through conduit 'lfi into vessel 72 containing filter B. From filter B the solvent is conducted, outside-in, into conduit 74 into the cooling unit 76 where the solvent temperature is maintained at approximately 80 F. From cooling unit 76 the solvent flows through conduit '73 into the cleaning drum 8% which typically has a rotatable interior drum 82 within which the fabrics to be cleaned are placed and revolved. After this cleaning cycle has been completed the solvent flows through conduit 84 into the perforated button trap 86 in the top of storage tank of to complete the circulation cycle. A pressure gage 90 is incorporated within the system, preferably in conduit 66, to give direct indications of filter and flow efficiencies.

Although the preferred embodiment of this invention contemplates the use of two separate filters it must be understood that one filter cartridge having incorporated therein the above described filtering and purifying system may be used. Also, the relative positions of the filters may be reversed and their general configurations varied without departing from the scope of this invention.

It has been found that this invention has its preferred application in small dry cleaning plants, generally the coin operated type. It is, however, not to be understood that this invention is to be limited to use in this type of dry cleaning plant as the theory and scope of the invention are equally applicable to all dry cleaning plants, regardless of size.

This invention has been described by reference to specific and preferred embodiments. It will be apparent, however, that many modifications can be made without departing from the spirit and scope of the invention. Accordingly, this invention should be construed not to be limited to the embodiments herein described but should be limited only by the scope of the appended claims.

What is claimed:

1. In a dry cleaning plant, a filtration system for dry cleaning solvents comprising a seriesed combination of first and second filter cartridges, the first cartridge comprising:

an outer perforated, substantially cylindrical cannister;

an inner perforated, substantially cylindrical cannister located ccaxially Within said outer cannister;

top and bottom closure plates connecting said cannisters and defining an annular space between them;

a sleeve of synthetic cloth material surrounding the exterior of said inner cannister;

a fatty acids-removing filtering medium substantially filling said annular space; the second cartridge comprising:

a first perforated, substantially cylindrical cannister;

a second perforated, substantially cylindrical cannister located coaxially within said first cannister;

top and bottom closure plates connecting said cannisters and defining an annular space between them;

said annular space being filled with a color and odor removing filtering medium; and

separate matted random fiber bristle blankets secured about the outer periphery of said first and said second cannisters.

2. A filtration system for dry cleaning solvents accord- References Qited by the Examiner UNITED STATES PATENTS 2,077,857 4/37 Seaton 68-181 2,098,713 11/37 Wesselrnann 210-335 X 2,141,903 12/38 Brundage 210-287 2,315,410 3/43 Simons et al. 8-142 X 2,338,158 1/44 Amsden 210-489 X 2,369,857 2/45 Russell et a1 210-283 X 3,066,519 12/62 Boswinkle et al 68-181 X 3,069,017 12/62 Colby 210-505 X MORRIS O. 'WOLK, Primary Examiner. 

1. IN A DRY CLEANING PLANT, A FILTRATION SYSTEM FOR DRY CLEANING SOLVENTS COMPRISING A SERIESED COMBINATION OF FIRST AND SECOND FILTER CARTRIDGES, THE FIRST CARTRIDGE COMPRISING: AN OUTER PERFORATED, SUBSTANTIALLY CYLINDRICAL CANNISTER; AN INNER PERFORATED, SUBSTANTIALY CYLIDRICAL CANNISTER LOCATED COAXIALLY WITHIN SAID OUTER CANNISTER; TOP AND BOTTOM CLOSURE PLATES CONNECTING SAID CANNISTERS AND DEFINING AN ANNULAR SPACE BETWEEN THEM; A SLEEVE OF SYNTHETIC CLOTH MATERIAL SURROUNDING THE EXTERIOR OF SAID INNER CANNISTER; A FATTY ACIDS-REMOVING GILTERING MEDIUM SUBSTANTIALLY FILLING SAID ANNULAR SPACE; THE SECOND CARTRIDGE COMPRISING: A FIRST PERFORATED, SUBSTANTIALLY CYLINDRICAL CANNISTER; A SECOND PERFORATED, SUBSTANTIALLY CYLINDRICAL CANNISTER LOCATED COAXIALLY WITHIN SAID FIRST CANNISTER; TOP AND BOTTOM CLOSURE PLATES CONNECTING SAID CANNISTERS AND DEFINING AN ANNULAR SPACE BETWEEN THEM; SAID ANNULAR SPACE BEING FILLED WITH A COLOR AND ODOR REMOVING FILTERING MEDIUM; AND SEPARATE MATTED RANDOM FIBER BRISTLE BLANKETS SECURED ABOUT THE OUTER PERIPHERY OF SAID FIRST AND SAID SECOND CANNISTERS. 